<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>盒子模型</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: red;
            padding: 30px;
            border: 5px solid green;
            margin: 50px;
        }
    </style>
</head>
<body>
    <div> </div>
    <p>哈哈</p>
</body>
</html>